Insights into the stable isotope ratio variability of hybrid grape varieties

Since 1998, the GiESCO (previously named GESCO: Groupe d’Etude des Systèmes de COnduite de la vigne) has provided the scientific community with relevant contributions to the study of terroirs. Here is a synthesis of the main terroir-related fields and the major ideas the GiESCO has developed: Basic Terroir Unit and climate, Vine Ecophysiology and microclimate – moderate drought, Vineyard heterogeneity and new technologies, Viticultural Terroir Unit and canopy management, Terroir – Territory and man.

Optimizing the use of water and improving irrigation strategies has become increasingly important in most winegrowing countries due to the consequences of climate change, which are leading to more frequent droughts, heat waves, or alteration of precipitation patterns. Optimized irrigation scheduling can only be based on a reliable knowledge of the vineyard water status.

In this context, this work aims at the development of a novel methodology, using a contactless, miniaturized, low-cost NIR spectral tool to monitor (on-the-go) the vineyard water status variability. On-the-go spectral measurements were acquired in the vineyard using a NIR micro spectrometer, operating in the 900–1900 nm spectral range, from a ground vehicle moving at 3 km/h. Spectral measurements were collected on the northeast side of the canopy across four different dates (July 8th, 14th, 21st and August 12th) during 2021 season in a commercial vineyard (3 ha). Grapevines of Vitis vinifera L. Graciano planted on a VSP trellis were monitored at solar noon using stem water potential (Ψs) as reference indicators of plant water status. In total, 108 measurements of Ψs were taken (27 vines per date).

Calibration and prediction models were performed using Partial Least Squares (PLS) regression. The best prediction models for grapevine water status yielded a determination coefficient of cross-validation (r2cv) of 0.67 and a root mean square error of cross-validation (RMSEcv) of 0.131 MPa. This predictive model was employed to map the spatial variability of the vineyard water status and provided useful, practical information towards the implementation of appropriate irrigation strategies. The outcomes presented in this work show the great potential of this low-cost methodology to assess the vineyard stem water potential and its spatial variability in a commercial vineyard.

AIM AND METHODS: Corvina and Corvinone are the two main grape varieties used in the production of Valpolicella, Recioto and Amarone, top-quality red wines in north-eastern Italy. This work aimed at determining the aroma composition of Corvina and Corvinone experimental wines and identify the main aroma compounds contributing to the aroma characteristics of Corvina and Corvinone monovarietal wines. Five Corvina and five Corvinone wines were studied, the grapes coming from five different vineyards in Valpolicella. Volatile compounds were extracted by SPE and identified and quantified by gas chromatography-mass spectrometry (GC-MS), whereas their aroma impact was determined by gas chromatography- olfactometry (GC-O).RESULTS: Based on the GC-MS-O analysis, 95 odor zones were detected, from which 68 compounds were successfully identified. Using the criterion of a value higher than 30% in modified frequency (MF %), 51 compounds were selected and grouped according to odor similarity. Compounds with values below 30% were discarded.

Xylotrechus arvicola (Coleoptera: Cerambycidae) is a pest in vineyards (Vitis vinifera) in the main Spain wine-producing regions with Protected Denomination of Origin (PDO). The action of the larvae, associated to the spreading of wood fungi, causes damage especially in important varieties of V. vinifera. X. arvicola females lay eggs concentrated in cracks or under the rhytidome in the wood vines, which allows the emerging larvae to get into the wood and make galleries inside the plant being then necessary to prune intensively or to pull up the bored plants (1). The objective of the study was to evaluate captures of X. arvicola insects in five varieties of V. vinifera in PDO León.

With wine fraud, being a widespread problem [1], the need for more sophisticated and precise analytical methods of its detection remains ever persistent.